Annihilator 2 is a sequel to the game Annihilator where you must get as many prisoners as you can to turn into slaves found on planets in the Messier 31 Galaxy. In this side-view horizontal shooter where the screen scrolls to the left or right when you move your spacecraft, you must fly over three stages for each planet to pick up the planet's inhabitants and all the aliens must be destroyed to move to the next stage. The first stage has you blasting all the aliens in space and as you blast you must avoid touching them or you lose one of three lives. The next stage has you flying over a mountain range and once again you must blast all the aliens to move to the next stage but there are missiles that are launched in to the air and also must be avoided. The final stage of a planet is the flatlands and as well as the various aliens to blast, on the surface are the inhabitants that can be picked up. Once the stages are complete, you then move to another planet and repeat the stages again.